Crossplow radiators



March 25, 1969 P. K. BEATENBOUGH ET AL Re. 26,550

CROSSFLOW RADIATORS Original Film] April u, 1963 7 4 INVENTORS 4L Pda/1K ed/eoow Y aid??? (1/ Eds/20p United States Patent 26,550 CROSSFLOWRADIATORS Paul K. Beatenbough, Medina, and Robert W. Bishop,

Lockport, N.Y., assignors to General Motors Corporation, Detroit, Mich.,a corporation of Delaware Original No. 3,275,070, dated Sept. 27, 1966,Ser. No. 271,743, Apr. 9, 1963. Application for reissue July 28, 1967,Ser. No. 661,148

Int. Cl. F28b 9/10, 3/00; F28d 1/02 US. Cl. 165111 4 Claims Mattterenclosed in heavy brackets appears in the original patent but forms nopart of this reissue specification; matter printed in italics indicatesthe additions made by reissue.

ABSTRACT OF THE DISCLOSURE A crossflow radiator in an automotive enginecooling system so constructed that sale expansion space as definedwithin the system for liquid coolant is in one tank of the radiator.

This invention refers to heat exchangers and more particularly to aradiator of the crossfiow type adapted to serve an internal combustionengine, and also to a combination of such a radiator with a liquidcooled internal combustion engine.

Crossfiow radiators have been used for many years. One reason for thecontinued efforts to use them is that they permit lower installation invehicles as compared with the more conventional downflow type.Heretofore, however, such radiators have been generally unacceptable.Expensive provisions for air removal and supplementary coolant reservetanks have been employed with crossflow radiators to insure that theradiator tube outlets are maintained full of engine coolant at alltimes. A common and basic difliculty has been that, as coolant isheated, it expands and some of it is lost through an overflow port. Asthe coolant subsequently cools and contracts, air is drawn into thesystem through the overflow port or a vacuum valve. If the air is notcollected at the overflow zone, the cooling system will act like a pumpto exhaust coolant with each heating and cooling cycle. In the teachingsof the United States patents to Muir, 1,860,783, granted May 31, 1932and 1,576,756, granted March 16, 1926, air vents are provided at thetops of outlet header tanks where air gathers but users of suchradiators continually replaced coolant in vain attempts to maintain toptanks full. Providing top header tanks eliminated a main advantage(lower installation) of crossfiow radiators and in the patentedstructures referred to, coolant loss is great because of the frequentrefills referred to.

It has now been discovered that top or supplementary coolant reservetanks are not necessary while the flow of coolant is maintained throughall tubes in a crossfiow radiator capable of stable and efiicientperformance i.e.an operation without the operator feeling it necessaryoften to check the coolant level.

To this end, an object of the present invention is to provide animproved crossflow radiator capable of elli- Re. 26,550 Reissued Mar.25, 1969 cient performance without the use of a top or added reservesupply tank. Another object is to provide an improved combination of anengine and a crossflow radiator.

A feature of the present invention is a crossfiow radiator comprising acore with tubes connecting two side tanks, one of the latter beingadapted to serve as a coolant inlet tank for receiving coolant and theother having means for removing air and being adapted to serve as acoolant outlet tank, the air removing means being above the outlet andthe coolant capacity of the radiator being sufiicient to include anecessary reserve supply of coolant in the absence of a top orsupplementary tank. Another feature is a combination of an engine and acrossflow radiator in which no reserve radiator tank in the form of atop, side or detached tank is employed.

These and other important features of the invention will now bedescribed in detail in the specification and then pointed out moreparticularly in the appended claims.

In the drawings:

FIGURE 1 shows a front elevation of an automobile engine with a directconnection to a radiator being shown diagrammatically, the radiatorbeing shown in perspective and the combination representing oneembodiment of the present invention;

FIGURE 2 is an elevation view of the radiator shown in FIGURE 1 anddrawn to a larger scale and with a por tion broken away better toillustrate the invention;

FIGURE 3 is a sectional view, drawn to a larger scale, looking in thedirection of the arrows 3-3 in FIGURE 2; and

FIGURE 4 is a sectional view drawn to the same scale as FIGURE 3 andlooking in the direction of the arrows 44 in FIGURE 2.

In the drawings, a typical automobile V-8 engine is illustrated at 10.This engine is provided with a coolant pump 12 and a pump outlet flowconnection 14 as well as a coolant jacket inlet connection 16. Acrossflow radiator is depicted at 18. This radiator has two side tanksaninlet tank 20 and an outlet tank 22. These two tanks are provided withan inlet 24 and an outlet 26 respectively. The inlet 24 is preferablybut not necessarily located in the top portion of the inlet tank 20. Theoutlet 26 is preferably located in a low portion of the outlet tank 22and is necessarily located below a vent connection 27 which communicateswith a top portion of the outlet tank 22 as will further appear. Thepump coolant outlet 14 and the radiator inlet 24 are directly connectedby a conduit diagrammatically represented by a dotted line 28. Theradiator outlet 26 and the engine jacket coolant inlet 16 are directlyconnected by a conduit diagrammatically represented by a dotted line 30.It will be noted that there are no supplementary tanks utilized in thecooling system of the illustrated combination of the engine 10 and theradiator 18.

In FIGURE 3, it is seen that horizontally extending tubes 32 of theradiator core 33 have ends passing through a tube sheet 34 and incommunication with the inlet tank 20. Air centers 36 in the form ofcorrugated thin sheets of metal are utilized in a conventional mannerbetween sets of adjacent rows of tubes 32 to enhance heat exchangecharacteristics of the radiator as is well known in the art. It will bealso understood that the tubes 32 communicate with the outlet tank 22 inthe same manner as depicted with relation to the inlet tank 20.

FIGURE 4 illustrates the relation of a radiator stiffening or framestructure 38 with respect to the core 33 with its air centers 36 andmultiple fiat tubes 32.

On the top of the outlet tank 22 is located a conventional pressure cap40 which seats on a shoulder 42 within a radiator filler neck 44. Itwill be understood that when a predetermined pressure is exceeded in theradiator or cooling system, a spring of the pressure cap will compressand the radiator will be vented by way of the vent 27. A cap suitablefor use in regulating the pressure is disclosed in the United StatesPatent 2,865,531 granted December 23, 1958 in the names of J. R. S.Gorst and S. W. Kemp.

In operation, engine coolant is forced by the pump 12 to How through theconduit 28 and into the inlet tank 20. The coolant then flowshorizontally through all the tubes 32 and is cooled by air flowingthrough the core 33 and by the fins or air centers 36. The air-cooledcoolant then flows into the outlet tank 22 which defines an integrated,substantially unrestricted, or free flow zone 50 served by the outlet 26and venting means generally indicated at 52 and including the closure 40and the vent pipe 27. The air-coolant interface in the outlet tanksmoves up and down in operation but this in no way interferes with theflow of coolant through the upper horizontal tubes 32. The zone 50 issized to fit other proportions and dimensiOns of a given cooling systemto permit the air-coolant interface to form. In a given design, if theHow rate were increased unduly, a condition would be reached at whichthe flow velocity in the zone 50 will sweep air along with it andthereby prevent air scparationi.e.-the flow velocity in a giveninstallation must be low enough to permit entrained air to separate forventing and in the zone having the vent. The de-aerated coolant thenreturns directly to the jacket of the engine by way of the conduit 30.

In the operation as above outlined, the cooling system depends upon pumppressure to force coolant through the radiator core 33 against the flowresistance of the latter. The cooling system is designed so that pumpflow rate exceeds the gravity flow rate through the radiator (that is,the fiow rate is such that the inlet tank 20 is maintained full ofwater). If this condition is met then flow occurs in only one horizontaldirection through the radiator and through all radiator tubes 32 withoutregard to the location of the air-water interface in the outlet tank 22.The size and shape of the inlet tank 20 are immaterial considerationsprovided that the tank 20 is not so small as to throttle pump flow rateto an extent that the latter falls below the radiator gravity fiow rate.Under the proper conditions described, air cannot separate in the inlettank 20 since it will be swept therefrom and by way of the radiator coretubes to the separation zone 50. If the pump flow rate is permitted tofall below the radiator gravity flow rate, the system will continue toseparate some air in the outlet tank but some air will also collect inthe upper portion of the inlet tank and coolant flow will cease throughthose radiator tubes which are above the air-coolant interface in theinlet tank. With proper pump pressure and no undue throttling of flowbetween the pump 12 and the core 33, the system and radiator willoperate in a stable and efficient fashion.

We claim:

1. A crossfiow radiator comprising only two elongated tanks each havinga vertical side, the said tanks being an inlet tank and an outlet tank,a core with tubes extending horizontally and connecting the verticalsides of said tanks to form flow passages leading from said inlet tankto said outlet tank, said inlet tank having a coolant inlet, said outlettank having a coolant outlet, a pressure actuated air vent connected toatmosphere and located at the top portion of said outlet tank in freecommunication with tubes of said core, the horizontal cross sectionalarea within the said top portion of said outlet tank being clear andsufliciently large relative to the coolant flow rate through the saidtubes to permit air to separate from said coolant upon the latterdischarging from said tubes into said outlet tank, and the path forfluid defined by said two tanks and tubes being in only one horizontaldirection.

2. A combination of an internal combustion engine coolant jacket with anengine coolant pump and a crossfiow radiator forming a closedcirculatory system, said radiator being an integral unit of only twotanks and a core with horizontally extending tubes, said tanks beingseparated by a space occupied by said core and having verticallyelongated facing sides serving as tube sheets for said tubes, one ofsaid tanks having a coolant inlet, conduit means in said system forminga direct connection between said jacket and pump to said coolant inlet,said conduit means defining a flow path of substantially constant crosssection to give a substantially uniform flow rate along its length, theother of said tanks having a top portion defining a zone in freecommunication with said tubes and having a sufficiently large volumerelative to the flow rate through the said tubes to permit air toseparate from coolant discharged by said tubes, said other tank having acoolant outlet located below said zone and connected to other conduitmeans forming part of said system, a pressure actuated air ventconnected to said zone, and the path for coolant flow defined by saidradiator being in only one horizontal direction.

3. A crossflow radiator in an internal combustion engine pressurizedcooling system including a coolant pump, said radiator comprising a pairof elongated tanks, said tanks being an inlet tank and an outlet tank, acore with tubes extending horizontally and connecting the said tanks toform flow passages leading from said inlet tank to solid outlet tank,said inlet tank having a coolant inlet, means connecting said pump tosaid coolant inlet, said outlet tank having a coolant outlet connectedto a low portion thereof, fluid discharge pressure actuated valve meansconnected to the top portion of said outlet tank and in freecommunication with the discharge ends of the top tubes of said core, thehorizontal cross sectional area of said top portion of said outlet tankbeing sufficiently large relative to the coolant flow rate through saidtubes to permil air to separate from said coolant upon the latterdischarging from said tubes into said top portion, and the said outlettank being the only expansion tank in said pressurized system.

4. A crossflow radiator in an internal combustion engine pressurizedcooling system including a coolant pump, said radiator comprisingelongated tanks connected by horizontal tubes, one of said tank having acoolant inlet, means connecting said inlet to said pump, the other ofsaid tanks being a radiator outlet rank having a coolant 0ul let leadingfrom a lower portion thereof and an expansion zone in the top thereof,pressure valve means associated with said outlet tank and connecting thesaid tubes and expansion zone to atmosphere for allowing fluid to escapefrom said system when the pressure in said zone rises to a predeterminedlevel above atmosphere pressure, the horizontal cross sectional areawithin the said zone being clear and sufiiciently large relative to thecoolant flow rate through the said tubes to permit air to separate fromsaid coolant upon the latter discharging from said tubes into saidoutlet tank, the said pump and radiator being so related that the pumpflow rate exceeds the gravity flow rate of said radiator, said pressurevalve means including vacuum valve means for allowing air to enter saidsystem when the pressure therein falls below atmosphere pressure, andthe said outlet tank defining the sole expansion zone in saidpressurized system.

(References on following page) patent.

References Cited UNITED STATES PATENTS The following references, citedby the Examiner, are of record in the patented file of this patent orthe original Ferguson 165-110 6 2,139,395 12/1938 Walker 123-4154 X3,077,927 2/1963 White et al. 165-110 X FOREIGN PATENTS 1,291,617 3/1962France.

LLOYD L. KING, Primary Examiner.

A. W. DAVIS, Assistant Examiner.

10 US. Cl. X.R.

